This invention relates to a cylindrical member transfer apparatus for grasping and transferring cylindrical members such as green cases or the like. More particularly, it relates to a tire building machine including the cylindrical member transfer apparatus for forming green tires by carcass bands and belt tread assemblies.
A cylindrical member transfer apparatus has been known is disclosed for example in Japanese Patent Application Publication No. 55-38,265. This apparatus includes carrying means mounted onto a center of an annular frame movable along rails for carrying a cylindrical tire constituting member at its center on its outside, and a pair of holding devices fixed to both ends of the annular frame for holding beads. In case that the tire constituting member is transferred and attached to a tire forming drum, first the beads are held by the holding devices, while the center of the tire constituting member is carried on its outside by the carrying means. The annular frame is then moved along the rails so that the tire constituting member is transferred to the forming drum to be fitted on its outside. Thereafter, the beads are set at predetermined positions at both the ends of the tire constituting member, and the tire constituting member is delivered from the carrying means to the tire forming drum.
If sizes of tires to be produced are changed, the set positions of the beads must be changed correspondingly. However, with the known transfer apparatus, it is very difficult to accommodate the change in size of tires because the holding means are mounted on the annular frame as above described. If the positions of the holding devices are shifted by loosening the mounting bolts, such an operation is very troublesome and time-consuming with resulting lower production efficiency.
Moreover, as the carrying means of the known apparatus supports the center of the tire constituting member, ends of the tire constituting member are likely to deform downwardly, particularly in case of a low strength constituting member, so that it becomes difficult to fit the member onto the forming drum.
On the other hand, a tire building machine has been known disclosed for example in U.S. Pat. No. 4,134,783. The disclosed building machine includes a belt forming drum for forming belt and tread assemblies by laminating belts and treads, a band forming drum so arranged whose axis perpendicularly intersects with an axis of the belt forming drum for forming carcass bands, a carcass drum arranged on the intersection of the axes of the belt and band forming drum and rotatable between a first position coaxial to the axis of the belt forming drum and a second position coaxial to the axis of the band forming drum, a carrier movable along the axis of the belt forming drum for transferring the belt and tread assembly from the belt forming drum to the carcass drum, and a transfer carrier movable along the axis of the band forming drum for transferring the carcass band from the band forming drum to the carcass drum. After the carcass band has been transferred from the transfer carrier to the carcass drum in the second position, the carcass drum is rotated to the first position and then shapes the carcass band into a toroidal shape. Thereafter, the belt and tread assembly which has been held by the carriers is attached on the carcass band to form a green tire.
As above described, with the prior art tire building machine, the carcass drum is arranged at the intersection of the axes of the belt forming and band forming drums. However, the carcass drum is inherently large because it must perform various operations such as the shaping operation, stitching operation and the like so that a wide space for the carcass drum is required in the proximity of the intersection. As a result, the belt forming drum and the band forming drum are greatly spaced apart from each other. Such forming drums are not yet completely automatized so that some manual operations by an operator are required. Therefore, the operator has to move in a wide area for his operations, with the result that the operator is forced to do hard work and the working efficiency is lowered. Moreover, as the large carcass drum is rotated, large power is required and at the same time forming accuracy is unavoidably lowered.